Luo Han Guo (whose Latin name is Siraitia grosvenorii) is a kind of perennial lianas belonging to the family Cucurbitaceae. Luo Han Guo is dioecious. It has heart-shaped leaves, blooms in summer and bears fruit in autumn. The fruit of Luo Han Guo contains medicinal ingredients such as mogroside, a variety of amino acids, vitamins and so on. In traditional Chinese Medicine, the fruit of Luo Han Guo can be used as a medicine to treat cough caused by lung heat, laryngopharyngitis, amygdalitis, acute gastritis, constipation and so on. Luo Han Guo is also known as a sweetener. It is widely used as a sweetening agent due to high sweetness and low calorie. Generally, Luo Han Guo is used as a substitute of sugar for patients with obese or diabetics.
Patent No. CN200910044558.9 provides a method for producing Luo Han Guo extract with the content of mogroside V being more than 60%. The process flow is crushing→saccharification→water extraction→concentration→centrifugal sedimentation→ion exchange resin refinement→macroporous resin refinement→concentration→alumina refinement→concentration→spray drying→end product. The method has a long process route, and a serial combination of macroporous resin and alumina is needed in separation and purification. Besides, the operation is complicated and the cost is high.
Patent No. CN200710003364.5 discloses a method for preparing Luo Han Guo extract which is decolorized and debitterized. In the method, the extracted liquid is filtrated, concentrated, decolorized with decolorizing resin and then eluted with ethanol, and debitterized with deodorant; afterward, concentration, spray drying and pulverization are performed to obtain the Luo Han Guo extract which is decolorized and debitterized. The weight content of mogroside V in the Luo Han Guo extract is 60% and more (HPLC). In this invention, macroporous resin is needed for adsorption and purification during separation and purification, and subsequently, an organic solvent is used for elution. Therefore, the operation is complicated and has a problem of solvent residue, and the cost is high.
Patent No. CN200710049737.2 provides a method for preparing milky white Luo Han Guo extract with the content of mogroside V being 40% or more and the content of mogroside being 98% or more. The method comprises steps of water extraction—concentration—enzymolysis—macroporous resin refinement—ion exchange resin decolorization—concentration—spray drying. In this invention, macroporous resin is needed for adsorption and purification during separation and purification, and subsequently, an organic solvent is used for elution. Therefore, the operation is complicated and has a problem of solvent residue, and the cost is high.
Currently, separation and purification of mogroside V mainly comprises the steps of using macroporous resin for adsorption, using different solvents for elution so as to obtain a crude extract with a certain amount of mogroside V, subjecting the crude extract to desalination and decolorization, and finally drying, sieving and packing the product. Besides, preparative chromatography and high speed countercurrent chromatography may also be used. Column chromatography is the most widely used, and macroporous adsorptive resins, such as resin type of D101 and AB-8, are most commonly used in the separation and purification. However, the operation of separation and purification with macroporous adsorptive resins is complicated, the yield of mogroside V is low, and the use of an organic solvent in elution leads to problems of solvent residue and environmental pollution. Although preparative chromatography and high speed countercurrent chromatography can achieve a high product content, equipment disposable investment is huge, the consumption of organic solvent is large, and problems such as solvent residue and environmental pollution still exist.